Penrith chairman Don Feltis will end a 60-year relationship with the club when the board officially accepts his resignation at a meeting on Wednesday.
Feltis, who was pivotal in the homecoming of general manager Phil Gould in 2011, has been involved with the club first as a player, then as a coach and administrator.
Gould confirmed that Feltis and fellow director John Hiatt tendered their resignations to the rest of the board last Friday.
"Chairman Don Feltis and deputy chairman John Hiatt last Friday informed the other members of the board that they would be standing down effectively immediately," Gould told 2GB radio.
"We've got board elections later this year and they're just giving the opportunity for new members to come onto the board and settle themselves before the next elections."
Feltis was CEO of the Panthers during their first premiership win in 1991 and served as a board member during their second grand final victory in 2003.
The former police officer was appointed chairman in 2009.
Feltis' decision to stand down is reportedly due to a health scare.
"They've given great service, both those gentlemen, for a long period of time," Gould said.
"It wasn't unexpected that some time around this time that they may be standing time. They just confirmed that. We'll give them the farewell they deserve."